sir how to specify axis for hollow geometry thanking in anticipation

For example you have a hollow cylider of radius r1 and r2.

If you define your central exis in the central axis of cylinders, still its alright as the domain will be considered as r2-r1 with the length L.

DC

but as this hollo portion is neither fluid nor solid so when we exort to fluent it wont take axis specification

Hey Vinayak Ofcourse you know how do subtract volumes in gambit don't you ?

Well, in case you don't: create 2 volumes of radius r1 and r2 and subtract r1 from r2 if r2>r1. Keep the subtracted volume and delete everything else.

DC

the other option would be to make the unwanted fluid zone into solid zone so that flow equations are not solved in this region.If you are also solving for energy equation,give a very low thermal conductivity to the solid region.

sri